U.S. patent number 11,078,212 [Application Number 16/428,082] was granted by the patent office on 2021-08-03 for 2-hydrocarbyl-3-(dihydroxyfluoresceinyl)phthalimidine monomers, methods of manufacture, and copolymers derived therefrom.
This patent grant is currently assigned to SHPP GLOBAL TECHNOLOGIES B.V.. The grantee listed for this patent is SABIC GLOBAL TECHNOLOGIES B.V.. Invention is credited to Rashmi R. Deshpande, Lohith Kenchaiah, James Alan Mahood, Hariharan Ramalingam, Vijayakumar Venkatesh Sugur.
United States Patent |
11,078,212 |
Kenchaiah , et al. |
August 3, 2021 |
2-hydrocarbyl-3-(dihydroxyfluoresceinyl)phthalimidine monomers,
methods of manufacture, and copolymers derived therefrom
Abstract
A purified 2-hydrocarbyl-3-(dihydroxyfluoresceinyl)phthalimidine
compound of formula (I): ##STR00001## wherein R is a C.sub.1-25
hydrocarbyl; each occurrence of R.sup.2 and R.sup.3 is
independently a halogen or a C.sub.1-25 hydrocarbyl; p is 0 to 4;
and each q is independently 0 to 3; and wherein the purified
2-hydrocarbyl-3-(dihydroxyfluoresceinyl)phthalimidine compound of
formula (I) has a purity of greater than 99.4%, as determined by
high performance liquid chromatography.
Inventors: |
Kenchaiah; Lohith (Bangalore,
IN), Sugur; Vijayakumar Venkatesh (Bangalore,
IN), Deshpande; Rashmi R. (Bangalore, IN),
Ramalingam; Hariharan (Bangalore, IN), Mahood; James
Alan (Evansville, IN) |
Applicant: |
Name |
City |
State |
Country |
Type |
SABIC GLOBAL TECHNOLOGIES B.V. |
Bergen Op Zoom |
N/A |
NL |
|
|
Assignee: |
SHPP GLOBAL TECHNOLOGIES B.V.
(Bergen op Zoom, NL)
|
Family
ID: |
62837835 |
Appl.
No.: |
16/428,082 |
Filed: |
May 31, 2019 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20200002349 A1 |
Jan 2, 2020 |
|
Foreign Application Priority Data
|
|
|
|
|
Jun 29, 2018 [EP] |
|
|
18181020 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C07D
491/10 (20130101); C07D 491/107 (20130101); C08G
64/12 (20130101); C08G 64/305 (20130101) |
Current International
Class: |
C07D
491/107 (20060101); C08G 64/30 (20060101) |
Field of
Search: |
;528/201
;514/19.2,19.3,409,412 ;548/409,410 ;546/12,15 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Other References
Yunfei Zuo,ab Xing Wang*a and Decheng Wu Uniting
aggregation-induced emission and stimuli-responsive
aggregation-caused quenching, single molecule achieved multicolour
luminescence; Journal of Materials Chemistry C., 2019, 7, 14555
(Year: 2019). cited by examiner .
Adamczyk et al., "Synthesis of Novel Spirolactams by Reaction of
Fluorescein Methyl Ester With Amines," 2000, 41, 807-809,
XP004188496; 4 pages. cited by applicant .
Database Reaxys, Database accession No. 628287 (Rx-ID), XP002783722
(D2a); Meyer, Spengler Chemische Be-Richte 1903, 36, 2949-2967
XP055498727 (D2b). cited by applicant .
Database Reaxys, Database accession No. 833786 (Rx-ID),
XP-002783721, (D1a); & Fischer; Hepp Chemische Berichte, 1893,
No. 26, 2236-2238, XP055498735 (D1b). cited by applicant .
Database Registry, Database Accession No. 1235007-92-7 (RN), Aug.
5, 2010, XP002783735. cited by applicant .
European Search Report; Application No. 18181020.1-1116; dated Aug.
18, 2018; 17 pages. cited by applicant .
European Search Report; Application No. 18181020.1-1116; dated Oct.
18, 2018; 15 pages. cited by applicant .
Fisher et al., "Ueber Fluoresceinanilid," Chemische Berichte, vol.
26, No. 2, May 1, 1893, pp. 2236-2238, Database Accession No.
833786, XP055498735, DE; 4 pages. cited by applicant .
Kang et al., Fluorescent and Colorimetric Detection of Acid Vapors
by Using Solid-Supported Rhodamine Hydrazides, (2009) 50, 201-2012,
XP025972763; 4 pages. cited by applicant.
|
Primary Examiner: Boykin; Terressa
Attorney, Agent or Firm: Cantor Colburn LLP
Claims
What is claimed is:
1. A purified 2-hydrocarbyl-3-(dihydroxyfluoresceinyl)phthalimidine
compound of formula (I) ##STR00017## wherein R is a C.sub.1-25
hydrocarbyl; each occurrence of R.sup.2 and R.sup.3 is
independently a halogen or a C.sub.1-25 hydrocarbyl; p is 0 to 4;
and each q is independently 0 to 3, and wherein the purified
2-hydrocarbyl-3-(dihydroxyfluoresceinyl)phthalimidine compound of
formula (I) has a purity of greater than 99.4%, as determined by
high performance liquid chromatography.
2. The compound of claim 1, wherein the compound is a purified
2-aryl-3-(dihydroxyfluoresceinyl)phthalimidine compound of formula
(IA) ##STR00018## wherein each occurrence of R.sup.1 is
independently a phenyl or a C.sub.1-6 alkyl; each occurrence of
R.sup.2 and R.sup.3 is independently a halogen or a C.sub.1-25
hydrocarbyl; p is 0 to 4; each q is independently 0 to 3; and r is
0 to 5, and wherein the purified
2-aryl-3-(dihydroxyfluoresceinyl)phthalimidine compound of formula
(IA) has a purity of greater than 99.4%, as determined by high
performance liquid chromatography.
3. The compound of claim 1, wherein the compound is a purified
2-aryl-3-(dihydroxyfluoresceinyl)phthalimidine compound of formula
(IB) ##STR00019## wherein each occurrence of R.sup.1 is
independently a phenyl or a C.sub.1-6 alkyl; each occurrence of
R.sup.2 is independently a halogen or a C.sub.1-25 hydrocarbyl; and
p and r are each independently 0 or 1, and wherein the purified
2-aryl-3-(dihydroxyfluoresceinyl)phthalimidine compound of formula
(IB) has a purity of greater than 99.4%, as determined by high
performance liquid chromatography.
4. The compound of claim 1, wherein the compound is a purified
2-phenyl-3-(dihydroxyfluoresceinyl)phthalimidine compound of
formula (IC) ##STR00020## wherein the purified
2-phenyl-3-(dihydroxyfluoresceinyl)phthalimidine compound of
formula (IC) has a purity of greater than 99.4%, as determined by
high performance liquid chromatography.
5. A method for the manufacture of the purified
2-hydrocarbyl-3-(dihydroxyfluoresceinyl)phthalimidine (I) compound
of claim 1, the method comprising: combining a primary amine of
formula (II) R--NH.sub.2 (II) with an aqueous acid to provide a
first reaction mixture; adding a fluorescein compound of formula
(III) ##STR00021## to the first reaction mixture to provide a
second reaction mixture; heating the second reaction mixture under
conditions effective to provide a third reaction mixture comprising
a crude phthalimidine; combining the crude phthalimidine and an
aqueous alkali solution to form an aqueous alkaline mixture;
contacting the aqueous alkaline mixture with an adsorbent to
provide a semi-purified phthalimidine; and mixing the semi-purified
phthalimidine with an alcohol solution to provide the purified
2-hydrocarbyl-3-(dihydroxyfluoresceinyl)phthalimidine compound of
formula (I), wherein, in formulas (I), (II), and (III), R is a
C.sub.1-25 hydrocarbyl; each occurrence of R.sup.2 and R.sup.3 is
independently a halogen or a C.sub.1-25 hydrocarbyl; p is 0 to 4;
and each q is independently 0 to 3.
6. The method of claim 5, further comprising one or more of mixing
the third reaction mixture with aqueous acid to provide the crude
phthalimidine; or contacting the aqueous alkaline mixture with the
adsorbent, then mixing with an acid to provide the semi-purified
phthalimidine.
7. The method of claim 5, further comprising mixing the
semi-purified phthalimidine with an alcohol solution and heating to
form a solution comprising the semi-purified phthalimide; and
contacting the solution with an adsorbent, then mixing with
deionized water to provide the purified
2-hydrocarbyl-3-(dihydroxyfluoresceinyl)phthalimidine compound of
formula (I).
8. The method of claim 5, further comprising one or more of:
isolating the crude phthalimidine from the third reaction mixture,
and then drying the crude phthalimidine; or isolating the
semi-purified phthalimidine, and then washing the semi-purified
phthalimidine.
9. The method of claim 8, wherein the isolating of the crude
phthalimidine comprises: mixing the third reaction mixture with
aqueous acid and water to provide the crude phthalimidine; and
filtering the crude phthalimidine.
10. The method of claim 8, wherein the isolating of the
semi-purified phthalimidine comprises: contacting the aqueous
alkaline mixture and the adsorbent with an acid to provide the
semi-purified phthalimidine; and filtering the semi-purified
phthalimidine.
11. The method of claim 5, wherein the heating of the second
reaction mixture is at 100 to 200.degree. C.
12. The method of claim 5, wherein the heating of the second
reaction mixture is for 10 to 40 hours.
13. The method of claim 5, wherein the heating of the second
reaction mixture is at 120 to 180.degree. C. for 15 to 35
hours.
14. The method of claim 5, wherein the primary amine is a primary
arylamine of formula (IIA) ##STR00022## wherein each occurrence of
R.sup.1 is independently phenyl or C.sub.1-6 alkyl; and r is 0 or
1.
15. The method of claim 5, wherein the primary amine is
aniline.
16. The method of claim 5, wherein the aqueous acid comprises an
aqueous solution of a mineral acid, and the aqueous alkali solution
comprises an aqueous solution of an alkali metal hydroxide or an
alkaline earth metal hydroxide.
17. The method of claim 5, wherein the primary amine of formula
(II) is present in the second reaction mixture at a concentration
of 2 to 5 molar equivalents of the fluorescein of formula (III),
and the aqueous acid is present in the first reaction mixture at a
concentration of 0.8 to 1.5 molar equivalents of the primary amine
of formula (II).
18. The method of claim 5, wherein the purity of the crude
phthalimidine is less than 99%, the purity of the semi-purified
phthalimidine is less than 99.5%, and the purity of the purified
2-hydrocarbyl-3-(dihydroxyfluoresceinyl)phthalimidine compound is
99.5% or greater.
19. A method for the manufacture of a polycarbonate, the method
comprising polymerizing the purified
2-hydrocarbyl-3-(dihydroxyfluoresceinyl)phthalimidine compound of
claim 1 in the presence of a carbonate source under conditions
effective to provide the polycarbonate.
20. The method of claim 19, wherein the polycarbonate comprises 0
to 0.8 weight percent of an impurity derived from the manufacturing
of the purified
2-hydrocarbyl-3-(dihydroxyfluoresceinyl)phthalimidine compound.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
This application claims priority to and the benefit of European
Patent Application No. 18181020.1, filed on Jun. 29, 2018, the
entire content of which is incorporated by reference herein.
BACKGROUND
This disclosure relates to methods for the manufacture of
2-hydrocarbyl-3-(dihydroxyfluoresceinyl)phthalimidines.
Phenolphthalein derivatives such as
2-phenyl-3,3-bis(4-hydroxyphenyl)phthalimidine (also known as
N-phenyl phenolphthalein bisphenol (PPPBP) or
3,3-bis(4-hydroxyphenyl)-2-phenylisoindolin-1-one)) have been used
as aromatic dihydroxy compound monomers to prepare polycarbonate
resins as well as polyarylate resins. Phenolphthalein derivatives
are attractive because they can be used, for example, in
polycarbonate copolymers to provide improved properties like higher
glass transition temperature (T.sub.g), high clarity, and excellent
mechanical properties. Currently available methods to synthesize
and isolate phenolphthalein derivatives are lengthy and resource
intensive. Additionally, purification of dihydroxy phenolphthalein
derivatives to reduce impurities such as phenolphthalein and
aminophenols can be difficult.
Accordingly, there remains a need for aromatic dihydroxy compound
monomers that can be prepared, purified, and incorporated into
copolymers to provide high heat stability, a higher T.sub.g, and
good transparency.
SUMMARY
Provided is a purified
2-hydrocarbyl-3-(dihydroxyfluoresceinyl)phthalimidine compound of
formula (I) is provided:
##STR00002## wherein R is a C.sub.1-25 hydrocarbyl, preferably a
C.sub.1-6 alkyl, a phenyl, or a phenyl substituted with up to five
C.sub.1-6 alkyl groups, more preferably a C.sub.1-3 alkyl or a
phenyl; each occurrence of R.sup.2 and R.sup.3 is independently
halogen or a C.sub.1-25 hydrocarbyl, preferably a halogen or a
C.sub.1-6 alkyl, more preferably a C.sub.1-3 alkyl; and p is 0 to
4, preferably 0 or 1, more preferably 0; and each q is
independently 0 to 3, preferably 0 or 1, more preferably 0; and
wherein the purified
2-hydrocarbyl-3-(dihydroxyfluoresceinyl)phthalimidine compound of
formula (I) has a purity of greater than 99.4%, preferably greater
than 99.5%, more preferably greater than 99.8%, as determined by
high performance liquid chromatography.
Also provided is a method for the manufacture of the purified
2-hydrocarbyl-3-(dihydroxyfluoresceinyl)phthalimidine (I) compound
of formula (I), which includes combining a primary amine of formula
(II). R--NH.sub.2 (II) with an aqueous acid to provide a first
reaction mixture; adding a fluorescein of formula (III)
##STR00003## to the first reaction mixture to provide a second
reaction mixture; heating the second reaction mixture under
conditions effective to provide a third reaction mixture comprising
a crude phthalimidine; combining the crude phthalimidine and an
aqueous alkali solution to form an aqueous alkaline mixture;
contacting the aqueous alkaline mixture with an adsorbent to
provide a semi-purified phthalimidine; and mixing the semi-purified
phthalimidine with an alcohol solution to provide the purified
2-hydrocarbyl-3-(dihydroxyfluoresceinyl)phthalimidine compound of
formula (I), wherein in formulas (I), (II), and (III), R is a
C.sub.1-25 hydrocarbyl, preferably a C.sub.1-6 alkyl, a phenyl, or
a phenyl substituted with up to five C.sub.1-6 alkyl groups, more
preferably a C.sub.1-3 alkyl or a phenyl; each occurrence of
R.sup.2 and R.sup.3 is independently a halogen or a C.sub.1-25
hydrocarbyl, preferably a halogen or a C.sub.1-6 alkyl, more
preferably a C.sub.1-3 alkyl; p is 0 to 4, preferably 0 or 1, more
preferably 0; and each q is independently 0 to 3, preferably 0 or
1, more preferably 0.
Also provided is a method for the manufacture of a polycarbonate
includes polymerizing the purified
2-hydrocarbyl-3-(dihydroxyfluoresceinyl)phthalimidine compound in
the presence of a carbonate source under conditions effective to
provide the polycarbonate.
In yet another aspect, a polycarbonate is manufactured by the
method disclosed herein, wherein the polycarbonate comprises 0 to
0.8 weight percent, preferably 0 to 0.5 weight percent, more
preferably 0 to 0.2 weight percent of an impurity derived from the
manufacturing of the purified
2-hydrocarbyl-3-(dihydroxyfluoresceinyl)phthalimidine compound.
The disclosure is further illustrated by the following detailed
description, examples, and claims.
DETAILED DESCRIPTION
The present disclosure is directed to
2-hydrocarbyl-3-(dihydroxyfluoresceinyl)phthalimidine compounds,
purified compounds thereof, the manufacture of the same, and
compositions, polymers, and articles derived therefrom. The
purified 2-hydrocarbyl-3-(dihydroxyfluoresceinyl)phthalimidine
compounds can be used in the manufacture of polycarbonates,
polycarbonate copolymers, and other polymers. The purified
2-hydrocarbyl-3-(dihydroxyfluoresceinyl)phthalimidine compound can
be prepared in a manner similar to the methods used to prepare
2-phenyl-3,3-bis(hydroxyphenyl)phthalimidine (PPPBP) monomers.
Unlike PPPBP, the
2-hydrocarbyl-3-(dihydroxyfluoresceinyl)phthalimidine compound can
be prepared as a product that is devoid of or contains a reduced
amount of undesirable impurities, for example aminophenol or
unreacted phenolphthalein impurities. The purified
2-hydrocarbyl-3-(dihydroxyfluoresceinyl)phthalimidine can be used
to provide polymers, such as polycarbonates and copolymers thereof,
with properties such as high heat stability, good color stability,
excellent clarity, and others.
The purified 2-hydrocarbyl-3-(dihydroxyfluoresceinyl)phthalimidine
compound in accordance with this disclosure is of formula (I):
##STR00004## wherein R is a C.sub.1-25 hydrocarbyl, preferably a
C.sub.1-6 alkyl, a phenyl, or a phenyl substituted with up to five
C.sub.1-6 alkyl groups, more preferably a C.sub.1-3 alkyl or a
phenyl. Each occurrence of R.sup.2 and R.sup.3 is independently a
halogen or a C.sub.1-25 hydrocarbyl, preferably a halogen or a
C.sub.1-6 alkyl, more preferably a C.sub.1-3 alkyl, p is 0 to 4,
and each q is independently 0 to 3. In some aspects, R is a
C.sub.1-6 alkyl, a phenyl, or a phenyl substituted with up to five
C.sub.1-6 alkyl groups. For example, R can be a C.sub.1-3 alkyl or
a phenyl. In some aspects, R.sup.2 and R.sup.3 are each
independently a halogen or a C.sub.1-6 alkyl, and p and q are each
independently 0 to 3. For example, R.sup.2 and R.sup.3 each can be
independently the same or different C.sub.1-3 alkyl, and p and q
are each independently 0 to 3. In some aspects, p and q are each
independently 0 or 1. For example, p can be 1 and R.sup.2 can be a
C.sub.1-3 alkyl group. In still other aspects, p and q are each
0.
The purified 2-hydrocarbyl-3-(dihydroxyfluoresceinyl)phthalimidine
compound of formula (I) can be of formula (IA)
##STR00005## wherein each occurrence of R.sup.1 is independently a
phenyl or a C.sub.1-6 alkyl; p is 0 to 4, q is 0 to 3, and r is 0
to 5, preferably 0 or 1. Each occurrence of R.sup.2 and R.sup.3 is
independently a halogen or a C.sub.1-25 hydrocarbyl, preferably a
halogen or a C.sub.1-6 alkyl, more preferably a C.sub.1-3 alkyl;
and q are each independently 0 to 3, preferably 0 or 1, more
preferably 0. In some aspects, R.sup.1 is a C.sub.1-3 alkyl and r
is 0 or 1. In certain aspects, R.sup.2 and R.sup.3 each can be
independently a C.sub.1-3 alkyl, and p and q are each independently
0 or 1. In some aspects, r is 0. In other aspects, p is 0.
When q is 0 in formulas (I) and (IA), the purified
2-hydrocarbyl-3-(dihydroxyfluoresceinyl)phthalimidine compound of
formula (I) can be of formula (IB)
##STR00006## wherein each occurrence of R.sup.1 is independently a
phenyl or a C.sub.1-6 alkyl, more preferably a C.sub.1-3 alkyl, and
r is 0 or 1. Each occurrence of R.sup.2 is independently a halogen
or a C.sub.1-25 hydrocarbyl, preferably a halogen or a C.sub.1-6
alkyl, more preferably a C.sub.1-3 alkyl, and p is 0 or 1. In some
aspects, R.sup.1 is a C.sub.1-3 alkyl and R.sup.2 is a C.sub.1-3
alkyl, and p and r each are 1. In other aspects, p and r are 0.
When p, q, and r are 0 in formulas (I), (IA), and (IB), the
purified 2-hydrocarbyl-3-(dihydroxyfluoresceinyl)phthalimidine
compound is of formula (IC)
##STR00007##
The purified 2-hydrocarbyl-3-(dihydroxyfluoresceinyl)phthalimidine
compound can be prepared by reaction of a substituted or
unsubstituted fluorescein compound and an acid salt of an amine
compound. For example, the method for the manufacture of the
purified 2-hydrocarbyl-3-(dihydroxyfluoresceinyl)phthalimidine
compound of formula (I) can include combining a primary amine of
formula (II) R--NH.sub.2 (II) with an aqueous acid to form a first
reaction mixture, and adding a fluorescein compound of formula
(III)
##STR00008## to the first reaction mixture to provide a second
reaction mixture. In formula (II), R can be a C.sub.1-25
hydrocarbyl, preferably a C.sub.1-6 alkyl, a phenyl, or a phenyl
substituted with up to five C.sub.1-6 alkyl groups, more preferably
a C.sub.1-3 alkyl or a phenyl. In formula (III), each occurrence of
R.sup.2 and R.sup.3 is independently a halogen or a C.sub.1-25
hydrocarbyl, preferably a halogen or a C.sub.1-6 alkyl, more
preferably a C.sub.1-3 alkyl; p can be 0 to 4, preferably 0 or 1,
more preferably 0; and each q can independently be 0 to 3,
preferably 0 or 1, more preferably 0. In some aspects, at least
some water is removed from the first reaction mixture before adding
the fluorescein compound.
The acid salt of the primary amine of formula (II) can isolated
from the first reaction mixture, and the acid salt of the primary
amine can be combined with the fluorescein of formula (III) to
provide the second reaction mixture. For example, the acid salt of
the primary amine of formula (II) can be isolated by mixing the
first reaction mixture with aqueous acid and water, and then
filtering the acid salt of the primary amine of formula (II). In
some aspects, the precipitated acid salt of the primary amine of
formula (II) an be dried, for example continuously dried, to
achieve a desired content or amount of water, for example less than
2 weight percent (wt %) of water, based on the weight of the acid
salt of the primary amine of formula (II).
Exemplary aqueous acids include, but are not limited to, mineral
acids. The mineral acids can be present in a fluid phase, for
example, in a gaseous phase or in a liquid phase or in a
combination of the gaseous and liquid phases. Non-limiting examples
of mineral acids include hydrogen chloride liquid, hydrogen
chloride gas, sulfuric acid, nitric acid, a combination thereof, or
the like.
The aqueous acid can be present in the first reaction mixture at a
concentration of 0.8 to 1.5 molar equivalents of the primary amine
of formula (II). For example, the aqueous acid can be present at a
concentration of 0.9 to 1.5, or 1 to 1.5, or 0.9 to 1.2 molar
equivalents of the primary amine of formula (II). As used herein,
the concentration of the aqueous acid in the first reaction mixture
refers to the molar equivalents of the aqueous acid that are
combined with the primary amine to provide the first reaction
mixture.
The primary amine of formula (II) can be present in the second
reaction mixture at a concentration of 2 to 5 molar equivalents of
the fluorescein of formula (III). For example, the primary amine of
formula (II) can be present in the second reaction mixture at a
concentration of 2.2 to 4.6, 2.4 to 4, 2.6 to 3.8, or 2.8 to 3.6
molar equivalents of the fluorescein of formula (III). As used
herein, the concentration of the primary amine in the second
reaction mixture refers to the concentration of the free amine.
The primary amine of formula (II) can be a primary arylamine of
formula (IIA)
##STR00009## wherein R.sup.1 and r are as described in formula (I).
In some aspects, the primary arylamine is aniline or a substituted
derivative thereof.
The second reaction mixture, which is formed by combining either
the first reaction mixture or the isolated acid salt of the primary
amine of formula (II) and the fluorescein of formula (III), can be
heated to provide a third reaction mixture including a crude
phthalimidine of formula (I). The second reaction mixture can be
heated at a suitable temperature and for a suitable time to provide
the third reaction mixture comprising the crude phthalimidine. For
example, the second reaction mixture can be heated at 100 to
200.degree. C. for 10 to 40 hours, preferably at 120 to 180.degree.
C. for 15 to 35 hours.
The third reaction mixture can be combined (e.g., mixed) with an
additional amount of aqueous acid to provide the crude
phthalimidine. The third reaction mixture can be heated after the
addition of the additional aqueous acid, for example at 80 to
150.degree. C. The amount of the additional aqueous acid can be
sufficient to convert the remaining primary amine of formula (II)
in the third reaction mixture to the corresponding acid salt.
In some aspects, the crude phthalimidine can be isolated from the
third reaction mixture and optionally dried. For example, the crude
phthalimidine can be isolated by combining (e.g., mixing) the third
reaction mixture with the additional amount of aqueous acid and
water, and then filtering the crude phthalimidine from the
mixture.
The crude phthalimidine can be combined with an aqueous alkali
solution to form an aqueous alkaline mixture. The aqueous alkali
solution can include an aqueous solution of an alkali metal
hydroxide, an alkaline earth metal hydroxide, or a combination
thereof. For example, the aqueous alkali solution can include
sodium hydroxide.
The aqueous alkali solution can be present at a concentration of
1.5 to 3.0 molar equivalents of the crude phthalimidine. For
example, the concentration of the aqueous alkali solution can be
1.5 to 2.5, or 1.75 to 2.75, or 2.0 to 3.0 molar equivalents of the
crude phthalimidine.
The aqueous alkaline mixture can be contacted with an adsorbent,
for example one or more of activated carbon, silica, alumina, clay,
a zeolite, or the like, to remove traces of one or more impurities
and to decolorize the mixture, to provide a semi-purified
phthalimidine of formula (I). For example, a commercially available
activated carbon can be used. Exemplary activated carbons include,
but are not limited to, the NORIT series of activated carbon
available from Norit Corporation, and those available from E. Merck
Company.
In some aspects, the aqueous alkaline mixture can be contacted one
or more times with the adsorbent to provide the semi-purified
product. In particular aspects, an acid can be combined with the
aqueous alkaline mixture after it is contacted with the adsorbent
to precipitate a solid product and provide the semi-purified
phthalimidine. The acid can be a dilute aqueous solution of a
mineral acid such as hydrochloric acid, sulfuric acid, nitric acid,
or the like. For example, the semi-purified phthalimidine can be
isolated by mixing with the acid, filtering the resulting solid
precipitate product, and then washing the semi-purified
phthalimidine with deionized water.
The semi-purified phthalimidine can be mixed with a solution
including an alcohol and water to form a purified
2-hydrocarbyl-3-(dihydroxyfluoresceinyl)phthalimidine compound of
formula (I). Exemplary alcohols include C.sub.1-6 alcohols such as
methanol, ethanol, isopropanol, or the like. For example, the
semi-purified product can be mixed with an alcohol solution
including methanol and water to form the purified phthalimidine
compound.
For example, the semi-purified phthalimidine can be combined with
an alcohol solution including an alcohol, for example methanol, and
deionized water, and then heated at 50-80.degree. C. to form a
solution. An adsorbent, for example a carbonaceous material, can be
added to the solution and the resulting mixture is stirred. The
adsorbent can then be separated from the solution and an additional
amount of deionized water can be added to the solution as needed to
provide the purified phthalimidine compound of formula (I).
The method can further include crystallizing the purified
2-hydrocarbyl-3-(dihydroxyfluoresceinyl)phthalimidine compound of
formula (I). For example, a slurry including the purified
2-hydrocarbyl-3-(dihydroxyfluoresceinyl)phthalimidine can be
concentrated to provide a concentrated slurry (e.g., 60 to 80%
solids), followed by separating a wet solid including the purified
2-hydrocarbyl-3-(dihydroxyfluoresceinyl)phthalimidine from the
concentrated slurry. Optionally, the wet solid can be re-slurried
(e.g., 12 to 30% solids), for example in a solution of methanol and
water (90:10 v/v), refluxed at the boiling point of the solvent and
cooled for example to -20.degree. C., or 5 to 10.degree. C., to
precipitate the purified
2-hydrocarbyl-3-(dihydroxyfluoresceinyl)phthalimidine. The wet
solid can then be isolated, for example by crystallization, and the
crystals separated from the mother liquor, for example by
filtration, and optionally dried to provide the purified
2-hydrocarbyl-3-(dihydroxyfluoresceinyl)phthalimidine.
The purified 2-hydrocarbyl-3-(dihydroxyfluoresceinyl)phthalimidine
compound of formula (I) can have a purity of greater than 99.4%,
preferably greater than 99.5%, more preferably greater than 99.8%,
as determined by high performance liquid chromatography (HPLC).
The purified
2-hydrocarbyl-3-(dihydroxyfluoresceinyl)phthalimidines, including
the exemplary purified
2-phenyl-3-(dihydroxyfluoresceinyl)phthalimidine (RPBP), are
commercially valuable monomers or comonomers for producing a
variety of polymers formed by reactions of the phenolic OH groups
of the 2-hydrocarbyl-3-(dihydroxyfluoresceinyl)phthalimidines.
Exemplary polymers that can be produced include homopolymers and
copolymers of a polycarbonate, a polyestercarbonate, a polyester, a
polyesteramide, a polyimide, a polyetherimide, a polyamideimide, a
polyether, a polyethersulfone, a polycarbonate-polyorganosiloxane
block copolymer, a copolymer comprising aromatic ester, ester
carbonate, and carbonate repeat units, and a polyetherketone. An
example of a copolymer including aromatic ester, estercarbonate,
and carbonate repeat units is the copolymer produced by the
reaction of a hydroxy-terminated polyester, such as the product of
reaction of isophthaloyl chloride and terephthaloyl chloride with
resorcinol, with phosgene and an aromatic dihydroxy compound, such
as bisphenol A.
According to some aspects, polycarbonates having low color
properties are synthesized, wherein the polycarbonates include
structural units of formula (VI)
##STR00010## that are derived from the purified
2-hydrocarbyl-3-(dihydroxyfluoresceinyl)phthalimidine compound of
formula (I), wherein R, R.sup.2, R.sup.3, p, and q are as described
previously; and the C.dbd.O structural units are derived from a
C.dbd.O donor such as a carbonic acid diester in a melt
transesterification process, or phosgene in an interfacial
process.
Specific polycarbonates include copolycarbonates having structural
units derived from a phthalimidine compound of formula (I) and a
dihydroxy compound of the formula HO--R.sup.1--OH, in particular of
formula (VII) HO-A.sup.1-Y.sup.1-A.sup.2-OH (VII) wherein each of
A.sup.1 and A.sup.2 is a monocyclic divalent aromatic group and
Y.sup.1 is a single bond or a bridging group having one or more
atoms that separate A.sup.1 from A.sup.2. In an exemplary
embodiment, one atom separates A.sup.1 from A.sup.2. Specifically,
each R.sup.1 can be derived from a dihydroxy aromatic compound of
formula (VIII)
##STR00011## wherein R.sup.a and R.sup.b each represent a halogen
or C.sub.1-12 alkyl group and can be the same or different; and p
and q are each independently integers of 0 to 4. X.sup.a represents
a single bond or a bridging group connecting the two
hydroxy-substituted aromatic groups, where the single bond or the
bridging group and the hydroxy substituent of each C.sub.6 arylene
group are disposed ortho, meta, or para (specifically para) to each
other on the C.sub.6 arylene group. For example, the bridging group
X.sup.a can be --O--, --S--, --S(O)--, --S(O).sub.2--, --C(O)--, or
a C.sub.1-18 organic group. The C.sub.1-18 organic group can be
cyclic or acyclic, aromatic or non-aromatic, and can further
include heteroatoms such as halogens, oxygen, nitrogen, sulfur,
silicon, or phosphorous. The C.sub.1-18 organic group can be
disposed such that the C.sub.6 arylene groups connected thereto are
each connected to a common alkylidene carbon or to different
carbons of the C.sub.1-18 organic group. In some aspects, p and q
is each 1, and R.sup.a and R.sup.b are each a C.sub.1-3 alkyl
group, specifically methyl, disposed meta to the hydroxy group on
each arylene group.
The group X.sup.a can be a substituted or unsubstituted C.sub.3-18
cycloalkylidene, a C.sub.1-25 alkylidene of formula
--C(R.sup.c)(R.sup.d)-- wherein R.sup.c and R.sup.d are each
independently hydrogen, C.sub.1-12 alkyl, C.sub.1-12 cycloalkyl,
C.sub.7-12 arylalkyl, C.sub.1-12 heteroalkyl, or cyclic C.sub.7-12
heteroarylalkyl, or a group of the formula --C(.dbd.R.sup.e)--
wherein R.sup.e is a divalent C.sub.1-12 hydrocarbon group.
Exemplary groups of this type include methylene,
cyclohexylmethylene, ethylidene, neopentylidene, and
isopropylidene, as well as 2-[2.2.1]-bicycloheptylidene,
cyclohexylidene, cyclopentylidene, cyclododecylidene, and
adamantylidene. Alternatively, the group X.sup.a can be a
C.sub.1-18 alkylene group, a C.sub.3-18 cycloalkylene group, a
fused C.sub.6-18 cycloalkylene group, or a group of the formula
--B.sup.1--W--B.sup.2-- wherein B.sup.1 and B.sup.2 are the same or
different C.sub.1-6 alkylene group and W is a C.sub.3-12
cycloalkylidene group or a C.sub.6-16 arylene group.
Other exemplary aromatic dihydroxy compounds of the formula
HO--R.sup.1--OH include compounds of formula (IX)
##STR00012## wherein each R.sup.h is independently a halogen atom,
a C.sub.1-10 hydrocarbyl such as a C.sub.1-10 alkyl group, a
halogen-substituted C.sub.1-10 alkyl group, a C.sub.6-10 aryl
group, or a halogen-substituted C.sub.6-10 aryl group, and n is 0
to 4. For example, the halogen can be bromine.
Exemplary aromatic dihydroxy compounds include
4,4'-dihydroxybiphenyl, 1,6-dihydroxynaphthalene,
2,6-dihydroxynaphthalene, bis(4-hydroxyphenyl)methane,
bis(4-hydroxyphenyl)diphenylmethane,
bis(4-hydroxyphenyl)-1-naphthylmethane,
1,2-bis(4-hydroxyphenyl)ethane,
1,1-bis(4-hydroxyphenyl)-1-phenylethane,
2-(4-hydroxyphenyl)-2-(3-hydroxyphenyl)propane,
bis(4-hydroxyphenyl)phenylmethane,
2,2-bis(4-hydroxy-3-bromophenyl)propane,
1,1-bis(hydroxyphenyl)cyclopentane,
1,1-bis(4-hydroxyphenyl)cyclohexane,
1,1-bis(4-hydroxyphenyl)isobutene,
1,1-bis(4-hydroxyphenyl)cyclododecane,
trans-2,3-bis(4-hydroxyphenyl)-2-butene,
2,2-bis(4-hydroxyphenyl)adamantane, alpha,
alpha'-bis(4-hydroxyphenyl)toluene,
bis(4-hydroxyphenyl)acetonitrile,
2,2-bis(3-methyl-4-hydroxyphenyl)propane,
2,2-bis(3-ethyl-4-hydroxyphenyl)propane,
2,2-bis(3-n-propyl-4-hydroxyphenyl)propane,
2,2-bis(3-isopropyl-4-hydroxyphenyl)propane,
2,2-bis(3-sec-butyl-4-hydroxyphenyl)propane,
2,2-bis(3-t-butyl-4-hydroxyphenyl)propane,
2,2-bis(3-cyclohexyl-4-hydroxyphenyl)propane,
2,2-bis(3-allyl-4-hydroxyphenyl)propane,
2,2-bis(3-methoxy-4-hydroxyphenyl)propane,
2,2-bis(4-hydroxyphenyl)hexafluoropropane,
1,1-dichloro-2,2-bis(4-hydroxyphenyl)ethylene,
1,1-dibromo-2,2-bis(4-hydroxyphenyl)ethylene,
1,1-dichloro-2,2-bis(5-phenoxy-4-hydroxyphenyl)ethylene,
4,4'-dihydroxybenzophenone, 3,3-bis(4-hydroxyphenyl)-2-butanone,
1,6-bis(4-hydroxyphenyl)-1,6-hexanedione, ethylene glycol
bis(4-hydroxyphenyl)ether, bis(4-hydroxyphenyl)ether,
bis(4-hydroxyphenyl)sulfide, bis(4-hydroxyphenyl)sulfoxide,
bis(4-hydroxyphenyl)sulfone, 9,9-bis(4-hydroxyphenyl)fluorine,
2,7-dihydroxypyrene,
6,6'-dihydroxy-3,3,3',3'-tetramethylspiro(bis)indane
("spirobiindane bisphenol"), 3,3-bis(4-hydroxyphenyl)phthalimide,
2,6-dihydroxydibenzo-p-dioxin, 2,6-dihydroxythianthrene,
2,7-dihydroxyphenoxathin, 2,7-dihydroxy-9,10-dimethylphenazine,
3,6-dihydroxydibenzofuran, 3,6-dihydroxydibenzothiophene, and
2,7-dihydroxycarbazole, resorcinol, substituted resorcinol
compounds such as 5-methyl resorcinol, 5-ethyl resorcinol, 5-propyl
resorcinol, 5-butyl resorcinol, 5-t-butyl resorcinol, 5-phenyl
resorcinol, 5-cumyl resorcinol, 2,4,5,6-tetrafluoro resorcinol,
2,4,5,6-tetrabromo resorcinol, or the like; catechol; hydroquinone;
substituted hydroquinones such as 2-methyl hydroquinone, 2-ethyl
hydroquinone, 2-propyl hydroquinone, 2-butyl hydroquinone,
2-t-butyl hydroquinone, 2-phenyl hydroquinone, 2-cumyl
hydroquinone, 2,3,5,6-tetramethyl hydroquinone,
2,3,5,6-tetra-t-butyl hydroquinone, 2,3,5,6-tetrafluoro
hydroquinone, 2,3,5,6-tetrabromo hydroquinone, or the like, or
combinations thereof.
The aromatic dihydroxy compound can be a bisphenol, such as
1,1-bis(4-hydroxyphenyl) methane, 1,1-bis(4-hydroxyphenyl) ethane,
2,2-bis(4-hydroxyphenyl) propane (hereinafter "bisphenol A" or
"BPA"), 2,2-bis(4-hydroxyphenyl) butane, 2,2-bis(4-hydroxyphenyl)
octane, 1,1-bis(4-hydroxyphenyl) propane, 1,1-bis(4-hydroxyphenyl)
n-butane, 2,2-bis(4-hydroxy-2-methylphenyl) propane,
1,1-bis(4-hydroxy-t-butylphenyl) propane, 3,3-bis(4-hydroxyphenyl)
phthalimidine, 1,1-bis(4-hydroxy-3-methylphenyl)cyclohexane
(DMBPC), or a combination thereof For example, the polycarbonate
can be a linear homopolymer derived from BPA, wherein A.sup.1 and
A.sup.2 are p-phenylene and Y.sup.1 is isopropylidene.
Exemplary carbonic acid diesters in the formation of the
polycarbonates in a melt transesterification process can be of
formula (X) (ZO).sub.2C.dbd.O (X) wherein each Z is independently
an unsubstituted or substituted C.sub.1-12 alkyl radical, or an
unsubstituted or substituted C.sub.6-22 aryl radical. Examples of
carbonic acid diesters include, but are not limited to, ditolyl
carbonate, m-cresyl carbonate, dinaphthyl carbonate, diphenyl
carbonate, diethyl carbonate, dimethyl carbonate, dibutyl
carbonate, dicyclohexyl carbonate, or a combination thereof.
Specific non-limiting examples of activated aromatic carbonates
include bis(o-methoxycarbonylphenyl)carbonate,
bis(o-chlorophenyl)carbonate, bis(o-nitrophenyl)carbonate,
bis(o-acetylphenyl)carbonate, bis(o-phenylketonephenyl)carbonate,
bis(o-formylphenyl)carbonate, or a combination thereof. Exemplary
ester-substituted diaryl carbonates include
bis(methylsalicyl)carbonate (CAS Registry No. 82091-12-1) (also
known as BMSC or bis(o-methoxycarbonylphenyl)carbonate), bis(ethyl
salicyl)carbonate, bis(propyl salicyl) carbonate, bis(butylsalicyl)
carbonate, bis(benzyl salicyl)carbonate, bis(methyl
4-chlorosalicyl)carbonate, or the like.
The melt transesterification process can be carried out by
combining a catalyst, the carbonic acid diester of formula (X), the
phthalimidine compound of formula (I), and optionally a dihydroxy
comonomer; and mixing the reaction mixture under reactive
conditions for a time period effective to produce the polycarbonate
product. Exemplary melt transesterification catalysts include
alkali metal compounds, alkaline earth metal compounds,
tetraorganoammonium compounds, tetraorganophosphonium compounds, or
a combination thereof. Example of alkali metal compounds or
alkaline earth metal compounds include sodium hydroxide, potassium
hydroxide, calcium hydroxide, magnesium hydroxide, sodium
bicarbonate, potassium bicarbonate, sodium carbonate, potassium
carbonate, lithium carbonate, sodium acetate, potassium acetate,
sodium stearate, potassium stearate, sodium hydroxyborate, sodium
phenoxyborate, sodium benzoate, potassium benzoate, lithium
benzoate, disodium hydrogen phosphate, dipotassium hydrogen
phosphate, dilithium hydrogen phosphate, disodium salts,
dipotassium salts, and dilithium salts of bisphenol A, and sodium
salts, potassium salts, lithium salts of phenol, or the like, or a
combination thereof. Exemplary tetraorganoammonium compounds and
tetraorganophosphonium compounds include tetramethylammonium
hydroxide, tetrabutylammonium hydroxide, tetraethylphosphonium
hydroxide, tetrabutylphosphonium acetate, tetrabutylphosphonium
hydroxide, or the like, or a combination thereof. For example, the
catalyst can be a combination of an alkali metal salt or alkaline
earth metal salt with at least one quaternary ammonium compound, at
least one quaternary phosphonium compound, or a combination
thereof. For example, the catalyst can include sodium hydroxide and
tetrabutylphosphonium acetate or tetramethylammonium hydroxide. The
catalyst can include the salt of a non-volatile inorganic acid, for
example alkali metal salts of phosphites; alkaline earth metal
salts of phosphites; alkali metal salts of phosphates; and alkaline
earth metal salts of phosphates, including NaH.sub.2PO.sub.3,
NaH.sub.2PO.sub.4, Na.sub.2H.sub.2PO.sub.3, KH.sub.2PO.sub.4,
CsH.sub.2PO.sub.4, Cs.sub.2H.sub.2PO.sub.4, or the like, or a
combination thereof. In some aspects, the transesterification
catalyst includes both the salt of a non-volatile acid and a basic
co-catalyst such as an alkali metal hydroxide. For example, a
combination of NaH.sub.2PO.sub.4 and sodium hydroxide as the
transesterification catalyst.
The catalysts can be used as combinations of two or more
substances. Moreover, the catalyst can be added in a variety of
forms. For example, the catalyst can be added as a solid powder, or
dissolved in a solvent, for example, in water, alcohol, or a
combination thereof. The total amount of catalyst can be
1.times.10.sup.-7 to 2.times.10.sup.-3 moles, and in other
embodiments, 1.times.10.sup.-6 to 4.times.10.sup.-4 moles, for each
mole of the combination of, for example, the purified RPBP and the
aromatic dihydroxy comonomer.
The polymerization reaction can be monitored by measuring the melt
viscosity or the weight average molecular weight of the reaction
mixture using techniques known in the art such as gel permeation
chromatography. These properties can be measured by taking discreet
samples or can be measured on-line. After the desired melt
viscosity or molecular weight is reached, the final polycarbonate
product can be isolated from the reactor in a solid or molten form.
The method of making polycarbonates can be a batch or a continuous
process.
The melt-polymerized polycarbonate can be prepared in an extruder
in the presence of one or more catalysts. The reactants for the
polymerization reaction can be fed to the extruder in powder or
molten form. For example, the reactants can be dry blended prior to
addition to the extruder. The extruder can be equipped with a
pressure reducing device (e.g., vents) that serve to remove the
activated phenol byproduct and thus drive the polymerization
reaction toward completion. The molecular weight of the
polycarbonate product can be manipulated by controlling, among
other factors, the feed rate of the reactants, the type of
extruder, the extruder screw design, and configuration, the
residence time in the extruder, the reaction temperature, and the
pressure reducing techniques present on the extruder. The molecular
weight of the polycarbonate product can also depend upon the
structures of the reactants and the catalyst employed.
Alternatively, the polycarbonates can be prepared by an interfacial
polymerization process. Although the reaction conditions for
interfacial polymerization can vary, an exemplary process involves
dissolving or dispersing a dihydric phenol reactant in aqueous
caustic soda or potash, adding the resulting mixture to a
water-immiscible solvent medium, and contacting the reactants with
a carbonate precursor in the presence of a catalyst such as
triethylamine or a phase transfer catalyst, under controlled pH
conditions, e.g., about 8-about 12. Exemplary water immiscible
solvents include methylene chloride, 1,2-dichloroethane,
chlorobenzene, toluene, or the like.
Exemplary carbonate precursors for interfacial polymerization
include a carbonyl halide such as carbonyl bromide or carbonyl
chloride, or a haloformate such as a bishaloformates of a dihydric
phenol (e.g., the bischloroformates of bisphenol A, hydroquinone,
or the like) or a glycol (e.g., the bishaloformate of ethylene
glycol, neopentyl glycol, polyethylene glycol, or the like).
Combinations comprising at least one of the foregoing types of
carbonate precursors can also be used. For example, phosgene can be
the carbonate precursor.
Phase transfer catalysts for interfacial polymerization include
tetraorganoammonium and tetraorganophosphonium compounds of the
formula (R.sub.3).sub.4Q.sup.+X, wherein each R.sup.3 is the same
or different, and is a C.sub.1-10 alkyl group; Q is a nitrogen or
phosphorus atom; and X is a halogen atom or a C.sub.1-8 alkoxy
group or C.sub.6-18 aryloxy group. Exemplary phase transfer
catalysts include, for example, [CH.sub.3(CH.sub.2).sub.3].sub.4NX,
[CH.sub.3(CH.sub.2).sub.3].sub.4PX,
[CH.sub.3(CH.sub.2).sub.5].sub.4NX,
[CH.sub.3(CH.sub.2).sub.6].sub.4NX,
[CH.sub.3(CH.sub.2).sub.4].sub.4NX,
CH.sub.3[CH.sub.3(CH.sub.2).sub.3].sub.3NX, and
CH.sub.3[CH.sub.3(CH.sub.2).sub.2].sub.3NX, wherein X is Cl.sup.-,
Br.sup.-, a C.sub.1-8 alkoxy group or a C.sub.6-18 aryloxy group.
An effective amount of a phase transfer catalyst can be about 0.1
to about 10 wt % based on the weight of bisphenol in the
phosgenation mixture. For example, the amount of phase transfer
catalyst can be 0.5 to 2 wt %, based on the weight of bisphenol in
the phosgenation mixture.
Any polycarbonate end group can be used, provided that such end
groups do not significantly adversely affect desired properties of
the compositions. Branched polycarbonate blocks can be prepared by
adding a branching agent during polymerization. A chain stopper
(also referred to as a capping agent) can be included during
polymerization. The chain stopper limits molecular weight growth
rate, and so controls molecular weight in the polycarbonate.
Exemplary chain stoppers include certain mono-phenolic compounds,
mono-carboxylic acid chlorides, or mono-chloroformates.
The interfacial method described above can be adapted to produce
polycarbonates through the intermediate formation of
2-hydrocarbyl-3-(dihydroxyfluoresceinyl)phthalimidine
bischloroformate, via the bischloroformate polymerization method.
The method includes reacting a
2-hydrocarbyl-3-(dihydroxyfluoresceinyl)phthalimidine with phosgene
in an organic solvent, and then reacting the bischloroformate
either with a
2-hydrocarbyl-3-(dihydroxyfluoresceinyl)phthalimidine, or an
aromatic dihydroxy compound in the presence of an acid acceptor and
an aqueous base to form the polycarbonate. The interfacial
polymerization method and the bischloroformate polymerization
method can be carried in a batch or a continuous mode using one or
more reactor systems. To carry out the process in a continuous
mode, one or more continuous reactors, such as for example, a
tubular reactor can be used. The continuous method can include
introducing into a tubular reactor system phosgene, a solvent
(e.g., methylene chloride), a bisphenol, an aqueous base, and
optionally a catalyst (e.g., a trialkylamine) to form a flowing
reaction mixture. The flowing mixture can be passed through the
tubular reactor system until substantially all of the phosgene has
been consumed. The resulting mixture can be treated with a
combination of an aqueous base, an endcapping agent, optionally a
solvent, and a catalyst. The endcapped polycarbonate thus formed
can be continuously removed from the tubular reactor system.
The processes disclosed herein can advantageously be used to
prepare, for example, RPBP homopolycarbonate and copolycarbonates
having a weight average molecular weight (M.sub.w) of 3,000 to
150,000 Dalton (Da) and a glass transition temperature (T.sub.g) of
80 to 300.degree. C. The number average molecular weight (M.sub.n)
of the homopolycarbonate and copolycarbonates can be from 1,500 to
75,000 Da.
The glass transition temperature can be determined, for example, by
differential scanning calorimetry (DSC). Glass transition
temperatures (T.sub.g) can be measured using thermal scans in a
range from 30 to 250.degree. C. under a nitrogen atmosphere with a
heating rate of 10 to 20.degree. C./min.
The molecular weight can be determined, for example, by gel
permeation chromatography (GPC) using polystyrene standards.
Polymers include structural units derived from the purified
phthalimidines, in particular RPBP, can be used to manufacture
polymer blends including units derived from the purified
phthalimidine and at least one other thermoplastic polymer.
Exemplary thermoplastic polymers include vinyl polymers,
(meth)acrylic polymers, polyacrylonitrile, polystyrenes,
polyolefins, polyesters, polyurethanes, polyamides, polysulfones,
polyimides, polyetherimides, poly(phenylene ethers), poly(phenylene
sulfides), poly(ether ketones), poly(ether ether ketones),
acrylonitrile-butadiene-styrene (ABS) polymers, poly(ether
sulfones), poly(alkenyl aromatic) polymers, polybutadiene,
polyacetals, polycarbonates, polyphenylene ethers, ethylene-vinyl
acetate copolymers, polyvinyl acetate, liquid crystal polymers,
ethylene-tetrafluoroethylene copolymer, aromatic polyesters,
polyvinyl fluoride, poly(vinylidene fluoride), poly(vinylidene
chloride), tetrafluoroethylene, polycarbonate-polyorganosiloxane
block copolymers, copolymers comprising aromatic ester,
estercarbonate, and carbonate repeat units, or a combination
thereof.
The polymers and polymer blends described hereinabove are valuable
for producing articles. Also provide herein is an article including
a polymer having structural units derived from the purified
2-hydrocarbyl-3-(dihydroxyfluoresceinyl)phthalimidine of formula
(I).
Polymers, particularly polycarbonate homopolymers and copolymers
comprising structural units derived from the high purity
2-hydrocarbyl-3-(dihydroxyfluoresceinyl)phthalimidine in general,
and RPBP in particular, exhibit reduced visual coloration. As such,
these polycarbonate polymers are useful for producing articles
having particular properties, such as lower visual color, among
others. The polycarbonate homopolymers and copolymers have high
glass transition temperatures of higher than or equal to about
180.degree. C. One of the unique properties of these
polycarbonates, especially those that have glass transition
temperatures of greater than or equal to about 180.degree. C. is
that during melt processing they exhibit a shear-thinning behavior.
That is, the polymers have the ability to flow under an applied
shear. Therefore, standard melt processing equipment used for BPA
polycarbonates can advantageously be used for producing articles.
The polycarbonates also have high transparency, as measured by
percent light transmission, of greater than or equal to about
85%.
Polycarbonate homopolymers and copolymers comprising structural
units derived from the high purity
2-hydrocarbyl-3-(dihydroxyfluoresceinyl)phthalimidine can have a
yellowness index (YI) of less than 10, preferably less than 5, more
preferably less than 2, even more preferably less than 0.5 as
measured on a 3 millimeter thick plaque in accordance with ASTM
D1925.
The polycarbonate polymers are useful for producing articles having
a number of useful properties, such as a low residual color. The
articles also exhibit excellent heat aging. Thus, extruded articles
have low color values (as measured by yellowness index, YI) even
after heat aging, such as, for example, a YI of less than 10,
preferably less than 5, more preferably less than 2 after heat
aging in air at 155 to 160.degree. C. for 500 hours, or a YI of
less than 5, preferably less than 2, more preferably less than 0.5
after heat aging in air at 120.degree. C. for 500 hours.
Also provided are thermoplastic compositions including the
polycarbonate polymers having structural units derived from the
purified 2-hydrocarbyl-3-(dihydroxyfluoresceinyl)phthalimidine. The
thermoplastic compositions can include various additives ordinarily
incorporated into polymer compositions of this type, with the
proviso that the additive(s) are selected so as to not
significantly adversely affect the desired properties of the
thermoplastic composition, in particular low color. Such additives
can be mixed at a suitable time during the mixing of the components
for forming the composition. The additive can be soluble or
non-soluble in polycarbonate. The additive composition can include
an impact modifier, flow modifier, filler (e.g., a particulate
polytetrafluoroethylene (PTFE), glass, carbon, mineral, or metal),
reinforcing agent (e.g., glass fibers), antioxidant, heat
stabilizer, light stabilizer, ultraviolet (UV) light stabilizer, UV
absorbing additive, plasticizer, lubricant, release agent (such as
a mold release agent), antistatic agent, anti-fog agent,
antimicrobial agent, colorant (e.g., a dye or pigment), surface
effect additive, radiation stabilizer, flame retardant, anti-drip
agent (e.g., a PTFE-encapsulated styrene-acrylonitrile copolymer
(TSAN)), or a combination thereof. For example, a combination of a
heat stabilizer, mold release agent, and ultraviolet light
stabilizer can be used. In general, the additives are used in the
amounts generally known to be effective. For example, the total
amount of the additive composition (other than any impact modifier,
filler, or reinforcing agent) can be 0.001 to 10.0 wt %, or 0.01 to
5 wt %, each based on the total weight of the polymer in the
composition.
The methods described herein are further illustrated by the
following non-limiting examples.
EXAMPLES
The components in Table 1 were used in the examples. Unless
specifically indicated otherwise, the amount of each component is
in weight percent (wt %) in the following examples, based on the
total weight of the composition.
TABLE-US-00001 TABLE 1 Component CAS number Source Fluorescein
2321-07-5 Sigma-Aldrich Aniline 62-53-3 Merck HCl 7647-01-0 Vetec
NaOH 1310-73-2 SD Fine Activated Charcoal 7440-44-0 SD fine
Diatomaceous Earth 61790-53-2 SD Fine
High performance liquid chromatography (HPLC) analysis was
generally carried out by using a solution of about 50 milligrams of
the sample dissolved in about 10 milliliters of methanol. The HPLC
instrument was equipped with a C18 (reverse phase) column
maintained at a temperature of 40.degree. C., and an ultraviolet
(UV) detector capable of detecting components at a wavelength of
230 nanometers (nm). A solvent mixture of methanol and water of
varying relative proportions was used. The flow rate was maintained
at 1 milliliter per minute. The purity was evaluated by area
normalization.
Example 1
140 g of aniline and 40 ml of 33% of HCl (33 wt % in water) were
combined in a four-neck round bottom flask fitted with an overhead
condenser, nitrogen inlet, and overhead stirrer. The reaction
mixture was stirred for 1 hour to provide an aniline hydrochloride
salt. 100 g of fluorescein was then added to the reaction mixture
and the resulting mixture was heated at 170.degree. C. for 30
hours. The progress of the reaction was monitored by thin layer
chromatography (TLC) using silica plates in a 1:1 solution of ethyl
acetate and hexanes. After completion of the reaction, the
temperature was reduced to 120.degree. C. and 150 ml of HCl (33 wt
% in water) was added to thereto to convert the remaining aniline
to the corresponding hydrochloride salt. 400 ml of deionized water
was subsequently added, and the resulting mixture was stirred for
one hour. The solids were filtered, collected, and dried at
120.degree. C. to provide a crude phthalimidine product. The purity
of the crude product was 81.7%, as determined by HPLC.
Example 2
50 g of the crude phthalimidine product from Example 1 and 500 ml
of an aqueous solution of NaOH (10 wt % in water) were combined in
three-neck round bottom flask fitted with a nitrogen inlet and an
overhead stirrer. The reaction mixture was stirred for one hour and
then filtered to remove the insoluble components. The filtrate was
collected and combined with 10 wt % of activated charcoal (based on
the weight of the crude product), stirred for 2 hours at 25.degree.
C., and then filtered over diatomaceous earth. The treatment with
activated charcoal was repeated a second time, and the resulting
filtrate was precipitated by the addition of HCl (dilute). The
resulting solid was isolated by filtration and washed with
deionized water to remove residual aniline chloride. The purity of
the semi-purified phthalimidine product was 99.3%, as determined by
HPLC.
Example 3
The semi-purified phthalimidine product was combined with a mixture
of methanol and water (90:10 vol/vol) and dissolved to form a
solution (20 wt % product) by heating at 60.degree. C. Activated
charcoal (10 wt % based on the weight of the crude product) was
added to the solution and the resulting mixture was stirred for one
hour at 60.degree. C. The mixture was filtered to separate the
activated charcoal and then diluted with deionized water (10 parts
by volume based on the total volume of the methanol and water
mixture). The mixture was stirred for 30 minutes at 25.degree. C.
The purified phthalimidine product was then isolated by filtration.
The purity of the purified phthalimidine product was 99.8%, as
determined by HPLC.
The purified phthalimidine product was further characterized by
liquid chromatography-mass spectrometry (LC-MS) and proton nuclear
magnetic resonance ('H-NMR) spectroscopy. LC-MS: m/z=406 Dalton
[M-H]. .sup.1H NMR: (DMSO-d.sub.6) .delta.=9.90 ppm (s, 2H), 7.29
ppm (d, 1H), 7.60 ppm (m, 2H), 7.15 ppm (m, 4H), 6.64 ppm (m, 4H),
and 6.55 ppm (m, 4H).
Table 2 summarizes the purity for Examples 1-3 as determined by
HPLC.
TABLE-US-00002 TABLE 2 Sample Purity Example 1 81.7% Example 2
99.3% Example 3 99.8%
The disclosure is further illustrated by the following non-limiting
Aspects.
Aspect 1: A purified
2-hydrocarbyl-3-(dihydroxyfluoresceinyl)phthalimidine compound of
formula (I)
##STR00013## wherein R is a C.sub.1-25 hydrocarbyl, preferably a
C.sub.1-6 alkyl, a phenyl, or a phenyl substituted with up to five
C.sub.1-6 alkyl groups, more preferably a C.sub.1-3 alkyl or a
phenyl; each occurrence of R.sup.2 and R.sup.3 is independently a
halogen or a C.sub.1-25 hydrocarbyl, preferably a halogen or a
C.sub.1-6 alkyl, more preferably a C.sub.1-3 alkyl; p is 0 to 4,
preferably 0 or 1, more preferably 0; and each q is independently 0
to 3, preferably 0 or 1, more preferably 0; and wherein the
purified 2-hydrocarbyl-3-(dihydroxyfluoresceinyl)phthalimidine
compound of formula (I) has a purity of greater than 99.4%,
preferably greater than 99.5%, more preferably greater than 99.8%,
as determined by high performance liquid chromatography.
Aspect 2: The compound of Aspect 1, wherein the compound is a
purified 2-aryl-3-(dihydroxyfluoresceinyl)phthalimidine compound of
formula (IA)
##STR00014## wherein each occurrence of R.sup.1 is independently a
phenyl or a C.sub.1-6 alkyl, preferably a phenyl or a C.sub.1-3
alkyl; each occurrence of R.sup.2 and R.sup.3 is independently a
halogen or a C.sub.1-25 hydrocarbyl, preferably a halogen or a
C.sub.1-6 alkyl, more preferably a C.sub.1-3 alkyl; p is 0 to 4,
preferably 0 or 1, more preferably 0; and each q is independently 0
to 3, preferably 0 or 1, more preferably 0; and wherein the
purified 2-aryl-3-(dihydroxyfluoresceinyl)phthalimidine compound of
formula (IA) has a purity of greater than 99.4%, preferably greater
than 99.5%, more preferably greater than 99.8%, as determined by
high performance liquid chromatography.
Aspect 3: The compound of Aspect 1, wherein the compound is a
purified 2-aryl-3-(dihydroxyfluoresceinyl)phthalimidine of formula
(IB)
##STR00015## wherein each occurrence of R.sup.1 is independently a
phenyl or a C.sub.1-6 alkyl, more preferably a phenyl or a
C.sub.1-3 alkyl; each occurrence of R.sup.2 is independently a
halogen or a C.sub.1-25 hydrocarbyl, preferably a halogen or a
C.sub.1-6 alkyl, more preferably a C.sub.1-3 alkyl; p is 0 to 4,
preferably 0 or 1, more preferably 0; and each q is independently 0
to 3, preferably 0 or 1, more preferably 0; and wherein the
purified compound of formula (IA) has a purity of greater than
99.4%, preferably greater than 99.5%, more preferably greater than
99.8%, as determined by high performance liquid chromatography;
preferably wherein each of p and r is zero, and the compound is a
purified 2-phenyl-3-(dihydroxyfluoresceinyl)phthalimidine compound
of formula (IC) as provided herein, wherein the purified compound
of formula (IC) has a purity of greater than 99.4%, preferably
greater than 99.5%, more preferably greater than 99.8%, as
determined by HPLC.
Aspect 4: The compound of aspect 1, wherein the compound is a
purified 2-phenyl-3-(dihydroxyfluoresceinyl)phthalimidine compound
of formula (IC)
##STR00016## wherein the purified
2-phenyl-3-(dihydroxyfluoresceinyl)phthalimidine compound of
formula (IC) has a purity of greater than 99.4%, as determined by
high performance liquid chromatography.
Aspect 5: A method for the manufacture of the purified
2-hydrocarbyl-3-(dihydroxyfluoresceinyl)phthalimidine (I) compound
of Aspect 1, the method comprising: combining a primary amine of
formula (II) as provided herein with an aqueous acid to provide a
first reaction mixture; adding a fluorescein of formula (III) as
provided herein to the first reaction mixture to provide a second
reaction mixture; heating the second reaction mixture under
conditions effective to provide a third reaction mixture comprising
a crude phthalimidine; combining the crude phthalimidine and an
aqueous alkali solution to form an aqueous alkaline mixture;
contacting the aqueous alkaline mixture with an adsorbent to
provide a semi-purified phthalimidine; and mixing the semi-purified
phthalimidine with an alcohol solution to provide the purified
2-hydrocarbyl-3-(dihydroxyfluoresceinyl)phthalimidine compound of
formula (I), wherein in formulas (I), (II), and (III), R is a
C.sub.1-25 hydrocarbyl, preferably a C.sub.1-6 alkyl, a phenyl, or
a phenyl substituted with up to five C.sub.1-6 alkyl groups, more
preferably a C.sub.1-3 alkyl or a phenyl; each occurrence of
R.sup.2 and R.sup.3 is independently a halogen or a C.sub.1-25
hydrocarbyl, preferably a halogen or a C.sub.1-6 alkyl, more
preferably a C.sub.1-3 alkyl; and p and q are each independently 0
to 4, preferably 0 or 1, more preferably 0.
Aspect 6: The method of Aspect 5, further comprising one or more of
mixing the third reaction mixture with aqueous acid to provide the
crude phthalimidine; or contacting the aqueous alkaline mixture
with the adsorbent, then mixing with an acid to provide the
semi-purified phthalimidine.
Aspect 7: The method of Aspect 5 or Aspect 6, further comprising
mixing the semi-purified phthalimidine with an alcohol solution and
heating to form a solution comprising the semi-purified
phthalimide; and contacting the solution with an adsorbent, then
mixing with deionized water to provide the purified
2-hydrocarbyl-3-(dihydroxyfluoresceinyl)phthalimidine compound of
formula (I).
Aspect 8: The method of any one or more of Aspects 5 to 7, further
comprising one or more of isolating the crude phthalimidine from
the third reaction mixture, then drying the crude phthalimidine,
preferably wherein the isolating comprises mixing the third
reaction mixture with aqueous acid and water, then filtering the
crude phthalimidine; or isolating the semi-purified phthalimidine,
then washing the semi-purified phthalimidine, preferably wherein
the isolating comprises mixing with an acid, then filtering the
semi-purified phthalimidine.
Aspect 8a: The method of Aspect 8, wherein the isolating of the
crude phthalimidine comprises: mixing the third reaction mixture
with aqueous acid and water to provide the crude phthalimidine, and
filtering the crude phthalimidine.
Aspect 8b: The method of Aspect 8, wherein the isolating of the
semi-purified phthalimidine comprises: contacting the aqueous
alkaline mixture and the adsorbent with an acid to provide the
semi-purified phthalimidine, and filtering the semi-purified
phthalimidine.
Aspect 9: The method of any one or more of Aspects 5 to 8, wherein
the heating the second reaction mixture is at 100 to 200.degree.
C., preferably at 120 to 180.degree. C.
Aspect 10: The method of any one or more of Aspects 5 to 9, wherein
the heating the second reaction mixture is for 10 to 40 hours,
preferably 15 to 35 hours.
Aspect 10a: The method of Aspect 10, wherein the heating of the
second reaction mixture is at 120 to 180.degree. C. for 15 to 35
hours.
Aspect 11: The method of any one or more of Aspects 5 to 10,
wherein the primary amine is a primary arylamine of formula (IIA)
as provided herein, wherein each occurrence of R.sup.1 is
independently phenyl or C.sub.1-6 alkyl, preferably a C.sub.1-3
alkyl; and r is 0 or 1, preferably 0.
Aspect 12: The method of any one or more of Aspects 5 to 11,
wherein the primary amine is aniline.
Aspect 13: The method of any one or more of Aspects 5 to 12,
wherein the aqueous acid comprises an aqueous solution of a mineral
acid, preferably hydrochloric acid, and the aqueous alkali solution
comprises an aqueous solution of an alkali metal hydroxide or an
alkaline earth metal hydroxide, preferably sodium hydroxide.
Aspect 14: The method of any one or more of Aspects 5 to 13,
wherein the primary amine of formula (II) is present in the second
reaction mixture at a concentration of 2 to 5, preferably 2 to 4
molar equivalents of the fluorescein of formula (III), and the
aqueous acid is present in the first reaction mixture at a
concentration of 0.8 to 1.5, preferably 0.9 to 1.2 molar
equivalents of the primary amine of formula (II).
Aspect 15: The method of any one or more of Aspects 5 to 14,
wherein the purity of the crude phthalimidine is less than 99%, the
purity of the semi-purified phthalimidine is less than 99.5%, and
the purity of the purified
2-hydrocarbyl-3-(dihydroxyfluoresceinyl)phthalimidine compound is
99.5% or greater.
Aspect 16: A method for the manufacture of a polycarbonate, the
method comprising polymerizing the purified
2-hydrocarbyl-3-(dihydroxyfluoresceinyl)phthalimidine compound of
any one or more of Aspects 1 to 4 or manufactured by the method of
any one or more of Aspects 5 to 16 in the presence of a carbonate
source under conditions effective to provide the polycarbonate.
Aspect 16a: The method of Aspect 16, wherein the polycarbonate
comprises 0 to 0.8 weight percent of an impurity derived from the
manufacturing of the purified
2-hydrocarbyl-3-(dihydroxyfluoresceinyl)phthalimidine compound.
Aspect 17: A polycarbonate manufactured by the method of Aspect 16,
wherein the polycarbonate comprises 0 to 0.8 weight percent,
preferably 0 to 0.5 weight percent, more preferably 0 to 0.2 weight
percent of an impurity derived from the manufacturing of the
purified 2-hydrocarbyl-3-(dihydroxyfluoresceinyl)phthalimidine
compound.
The compositions, methods, and articles can alternatively comprise,
consist of, or consist essentially of, any appropriate materials,
steps, or components herein disclosed. The compositions, methods,
and articles can additionally, or alternatively, be formulated so
as to be devoid, or substantially free, of any materials (or
species), steps, or components, that are otherwise not necessary to
the achievement of the function or objectives of the compositions,
methods, and articles.
All ranges disclosed herein are inclusive of the endpoints, and the
endpoints are independently combinable with each other (e.g.,
ranges of "up to 25 wt %, or, more specifically, 5-20 wt %", is
inclusive of the endpoints and all intermediate values of the
ranges of "5 wt % to 25 wt %," etc.). "Combinations" is inclusive
of blends, mixtures, alloys, reaction products, and the like. The
terms "a" and "an" and "the" do not denote a limitation of
quantity, and are to be construed to cover both the singular and
the plural, unless otherwise indicated herein or clearly
contradicted by context. "Or" means "and/or" unless clearly stated
otherwise. Reference throughout the specification to "some
aspects", "an aspect", and so forth, means that a particular
element described in connection with the aspect is included in at
least one aspect described herein, and may or may not be present in
other aspects. In addition, it is to be understood that the
described elements can be combined in any suitable manner in the
various aspects. As used herein, "a combination thereof" is an open
term that includes any combination of the listed components and can
further include other components that are similar.
Unless defined otherwise, technical and scientific terms used
herein have the same meaning as is commonly understood by one of
skill in the art to which this application belongs. All cited
patents, patent applications, and other references are incorporated
herein by reference in their entirety. However, if a term in the
present application contradicts or conflicts with a term in the
incorporated reference, the term from the present application takes
precedence over the conflicting term from the incorporated
reference.
"Hydrocarbyl" as used herein refers to a monovalent moiety formed
by removing a hydrogen atom from a hydrocarbon. Representative
hydrocarbyls are alkyl groups having 1 to 25 carbon atoms, such as,
for example, methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl,
octyl, nonyl, undecyl, decyl, dodecyl, octadecyl, nonadecyl,
eicosyl, heneicosyl, docosyl, tricosyl, and the isomeric forms
thereof; aryl groups having 6 to 25 carbon atoms, such as
ring-substituted and ring-unsubstituted forms of phenyl, tolyl,
xylyl, naphthyl, biphenyl, tetraphenyl, and the like; arylalkyl
groups having 7 to 25 carbon atoms, such as ring-substituted and
ring-unsubstituted forms of benzyl, phenethyl, phenpropyl,
phenbutyl, naphthoctyl, and the like; and cycloalkyl groups, such
as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl,
cyclooctyl, and the like. The term "alkyl" means a branched or
straight chain, unsaturated aliphatic hydrocarbon group, e.g.,
methyl, ethyl, n-propyl, i-propyl, n-butyl, s-butyl, t-butyl,
n-pentyl, s-pentyl, and n- and s-hexyl. "Alkenyl" means a straight
or branched chain, monovalent hydrocarbon group having at least one
carbon-carbon double bond (e.g., ethenyl (--HC.dbd.CH.sub.2)).
"Alkoxy" means an alkyl group that is linked via an oxygen (i.e.,
alkyl-O--), for example methoxy, ethoxy, and sec-butyloxy groups.
"Alkylene" means a straight or branched chain, saturated, divalent
aliphatic hydrocarbon group (e.g., methylene (--CH.sub.2--) or,
propylene (--(CH.sub.2).sub.3--)). "Cycloalkylene" means a divalent
cyclic alkylene group, --C.sub.nH.sub.2n-x, wherein x is the number
of hydrogens replaced by cyclization(s). "Cycloalkenyl" means a
monovalent group having one or more rings and one or more
carbon-carbon double bonds in the ring, wherein all ring members
are carbon (e.g., cyclopentyl and cyclohexyl). "Aryl" means an
aromatic hydrocarbon group containing the specified number of
carbon atoms, such as phenyl, tropone, indanyl, or naphthyl.
"Arylene" means a divalent aryl group. "Alkylarylene" means an
arylene group substituted with an alkyl group. "Arylalkylene" means
an alkylene group substituted with an aryl group (e.g.,
benzyl).
The prefix "halo" means a group or compound including one more of a
fluoro, chloro, bromo, or iodo substituent. A combination of
different halo groups (e.g., bromo and fluoro), or only chloro
groups can be present. "Halogen" or "halogen atom" as used herein
refers to a fluorine, chlorine, bromine, or iodine atom.
The prefix "hetero" means that the compound or group includes at
least one ring member that is a heteroatom (e.g., 1, 2, or 3
heteroatom(s)), wherein the heteroatom(s) is each independently N,
O, S, Si, or P.
"Substituted" means that the compound, group, or atom is
substituted with at least one (e.g., 1, 2, 3, or 4) substituents
instead of hydrogen, where each substituent is independently nitro
(--NO.sub.2), cyano (--CN), hydroxy (--OH), halogen, thiol (--SH),
thiocyano (--SCN), C.sub.1-6 alkyl, C.sub.2-6 alkenyl, C.sub.2-6
alkynyl, C.sub.1-6 haloalkyl, C.sub.1-9 alkoxy, C.sub.1-6
haloalkoxy, C.sub.3-12 cycloalkyl, C.sub.5-18 cycloalkenyl,
C.sub.6-12 aryl, C.sub.7-13 arylalkylene (e.g., benzyl), C.sub.7-12
alkylarylene (e.g., toluyl), C.sub.4-12 heterocycloalkyl,
C.sub.3-12 heteroaryl, C.sub.1-6 alkyl sulfonyl
(--S(.dbd.O).sub.2-alkyl), C.sub.6-12 arylsulfonyl
(--S(.dbd.O).sub.2-aryl), or tosyl
(CH.sub.3C.sub.6H.sub.4SO.sub.2--), provided that the substituted
atom's normal valence is not exceeded, and that the substitution
does not significantly adversely affect the manufacture, stability,
or desired property of the compound. When a compound is
substituted, the indicated number of carbon atoms is the total
number of carbon atoms in the compound or group, excluding those of
any substituents. For example, a group having the formula
--CH.sub.2CH.sub.2CN is a C.sub.2 alkyl group substituted with a
cyano substituent.
While particular aspects have been described, alternatives,
modifications, variations, improvements, and substantial
equivalents that are or may be presently unforeseen may arise to
applicants or others skilled in the art. Accordingly, the appended
claims as filed and as they may be amended are intended to embrace
all such alternatives, modifications variations, improvements, and
substantial equivalents.
* * * * *